Rabbling arm for roasting furnaces



July 3, 1923;

' D. BAIRD RA'BBLING ARM FOR ROASTING FURNACES IIVVE/VTUR puma 58mm)ATTORNEYS 7/ ill lqu Filed Feb. 5.

lllllll \EI 1 WITNESSES Patented July 3, 1923.

'umrao stares Marat PAT CHEMICAL Coll L.

PANY, OF NEW YORK, N. Y., A CORPORATION'OFNEW YORK.

RABBLING- ARM FOE ROASTIN G FURNACES.

Application filed February 5, 1920. Serial No. 356,553.

of passages connectmg respectively with a.

plurality of passages in the central shaft (see, for instance, UnitedStates Letters Patent to Herreshoff, No. 976,175, November 22, 1910),and has for its object to improve the construction of the rabble armsthereof.

The particular object of my invention is a rabble arm embodying anexternal tubular member which supports the rabble teeth, and an internaltubular member through which latter a cooling fluid such as air may beintroduced to the interior-of the external member to reduce thetemperature thereof. The novel features of my invention are pointedoutin the appended claims.

My invention may be embodied for instance in a construction such asshown, for purpose of illustration, in the drawing, in which Fig.1 is ahorizontal section of a rabble arm and ofthe central rotatable shaft ofthe furnace to which it is attached, ig. 2 is a vertical section of aportion of my rabble arm and of so much of the central rotatable'shaftas is necessary to illustrate the connection between rabble arm andshaft; Fig. 3 is an end'view of the inner end of therabble arm; Fig. 1is a top view, and Fig. 5 abottomview, 0f the inner end of my rabblearm. I

The central rotatable shaft is' formed in any suitable manner so as tohave acentral passage enclosed by'an inner wall 1 and an annular passageenclosed between said inner wall 1 and-an outer wall 2; ribs 3, 3 arepreferably provided in order to increase the rigidity of the centralshaft in the region of the connection with the rabble arm. Suitableopenings are provided in the inner and outer walls to receive the end ofthe rabble arm, the opening in the outer wall being preferablysurrounded and defined by an annular flange such as 2. The rabble madeof any suitable material, steel, and is attached by frictional engage--ment or otherwise to the supporting means 5 for thepurpose ofwithdrawing the arm consists of-an outer member 4 of any suitabletubular end thereof to permit access to the interior from such end. Itmay be made of any suitable material, but is preferably madeo'f castiron, and isarranged to support rabbleteeth of any desired construction,for instance those shown in United States Letters Patent, No. 1,231,408,July 24, 1917. This outer arm is provided with supporting means such asribs 55 arranged in the interior portion of the inner extremity of therabble arm. These supporting means preferably extend formed betweenwalls 1 and2 and preferably terminate in a joint forming member such asthe ferrule 7 adapted tomake-close contact with the walls of theaperture in the inner wall 1. The interior member 6 of the rabble arm isof tubular-shape, and may be preferably and preferably member; 7 i

The flange 2 is preferably provided with an opening in its upperportion, and the exalso tothe joint forming ternal member with acorresponding opening near its inner end, such openings being adapted tobe placed 1n allgnment. When these openings are-1n alignment alock pin 8may be inserted thereinto so as to lock the arm and rotary shaft inproper relationship; The lock pin 8 may be of any suitable constructionand is preferably provided witlr a head of a larger diameter than theshank and with a stop shoulder at a distance from the head to limit themovement of. the pin into the openings and to provide a space into whichthe end of a suitable tool is inserted as to permit the removal of the:arm from the rotary shaft 'inthe manner fully described inUnited StatesLetters PatentNo. 1,191,818, July 18, 1916. r

In order to permit a ready alignment of these two openings preparatoryto the insertion of the'lock pin 8, the flange 2,and"

the external member 4, may be provided with suitable positioning meanssuch as the Wedge-shaped extension piece 2 on the shape, and may includeany features commonly found in arms of'this; type for instance theopening at the outer .into the annular chamber pin'so NT w e.

- DUDLEY BAIRD, OF BERKELEY, CALIFORNIA, ASSIGNOR T0 GENERAL former, andtwo suitably spaced stop members L on the latter adapted to engage withsaid extension piece when the relation of the flange and rabble arm issuchthat the two openings are in alignment.

When it is desired to remove the arm for purpose of repair or exchange,the lock pin 8 is removed and the arm is pulled away, preferably throughthe open furnace door. N hen the exterior member is removed, theinterior member, being attached thereto, is removed with it, and whenthe arm is inserted in place but one operation is necessary as bothinterior member and exterior member are combined in the form of a unit,and are so arranged that no part of the interior member comes in contactwith any part of the central shaft. It is necessary, therefore, toadjust the relation of only two elements, to wit, the external member ofthe rabble arm and the central shaft, instead of, as heretofore,adjusting the exterior member and the interior member separately todifferent por- 'tions of the central shaft structure. This forms one ofthe advantages of my invention.

Another advantage of my invention, as embodied in the str uoture shownin the drawings, is that the interior member is supported at pointslocated outside of the periphery of the central shaft while yet havingits outer end free, instead of being supported only bythe inner wall ofthe central shaft as in various constructions known to the prior art, orof being supported at one or more points nearer the outer end of therabble arm. It is obvious that in that por tion of the rabble armdirectly exposed to the hot furnace gases the circulation should be freeas possible, and that therefore any contact between the interior memberand the exterior member in. such portion should be avoided, and this Ihave accomplished by placin my support within that portion of the rabblearm which is protected by the central shaft and the flange 2'. Inaddition to their other functions, the ribs 5, which, in the illustratedexample, constitute the support referred to, define radial fluidpassages between the interior and exterior members near the inner endsthereof.

In my construction the interior member may be supported in its entiretyby the exterior member, while still extending centrally thereof, so asto permit a free circulation of the cooling medium along the entireinner surface of the exterior member except such small portion thereofas is occupied by the supporting means for the interior member.

It is obvious that I may embody my invention in constructions other thanthose shown in the drawings, and that for instance the form, arrangementand attachment of the supporting members may be varied, and that thearrangement for uniting the rabble arm to the central shaft may bevaried, in many ways, without departing from the spirit of my invention.It is, of course, obvious, that the invention is applicable only to thetype of rabble arm which permits connection of the external member andof the internal member, with two passages, respectively, in a central.shaft, to permit circulation of a cooling fluid, such as air, throughsaid members, and it is to a rabble arm of this type to which I refer inmy claims.

I claim:

1. A rabble arm construction of the type described comprising anexternal tubular member, an internal tubular member, means provided atthe inner end of said external member for supporting said internalmember within the external member and spaced from the walls thereof,said means being located partly without said external member anddefining radial fluid passages between said members, and a jointformingmember carried by said supporting means exteriorly of said externalmember.

2. A rabble arm construction of the type described comprising anexternal tubular member, an internal tubular member projecting beyondthe inner end of said external member, radially-extending devices spacedfrom each other on one of said members near the inner end thereof forsupporting said internal member within the external member and spacedfrom the walls thereof, said de- Vices projecting beyond the inner endof said external member, and a joint-forming member carried by the outerends of said devices.

3. A rabble arm construction of the type described comprising a tubularmember, radially extending devices spaced from each other attached tosuch member and projecting beyond the same, a joint forming membercarried by the outer ends of said devices, and an internal tubularmember supported by said devices and extending to said joint formingmember.

In testimony whereof I have hereto set my hand.

DUDLEY BAIRD.

